Reverberators for use in wide band assisted reverberation systems

A multi-channel reverberation system has a substantially constant multi-channel power gain at audio frequencies and comprises multiple signal inputs, one for each input channel, a number of comb filter networks connected to each signal input, each comb filter network including a feed forward stage, a cross-coupling network cross-coupling the comb filters to increase the reverberation echo density, and multiple signal outputs, one for each output channel. Preferably the feed forward stage of each comb filter provides a substantially constant multi-channel power gain at audio frequencies and the cross-coupling matrix is an orthogonal cross-coupling matrix cross-coupling a number of single channel allpass comb filters, positioned immediately before or after the delay lines, to create a multi-channel allpass comb filter with a unitary transfer function matrix at all frequencies.

Skip to:  ·  Claims  ·  References Cited  · Patent History  ·  Patent History

Claims

1. A multi-channel reverberation system comprising:

multiple signal inputs, one for each input channel;
a number of feed back comb filter networks connected one to each signal input, each comb filter network including a feed forward stage to provide a substantially constant multi-channel power gain at audio frequencies;
a cross-coupling network cross-coupling the comb filters to increase the reverberation echo density;
and multiple signal outputs, one for each output channel.

2. A multi-channel reverberation system according to claim 1, wherein the feed forward stage of the comb filters provides a transfer function matrix which is unitary at each frequency in the audio range.

3. A multi-channel reverberation system according to claim 1, wherein the cross-coupling matrix is an orthogonal cross-coupling matrix cross-coupling a number of single channel allpass comb filters, positioned immediately before or after the delay lines, to create a multi-channel allpass comb filter with a unitary transfer function matrix at all frequencies.

Referenced Cited
U.S. Patent Documents
4338581 July 6, 1982 Morgan
4366346 December 28, 1982 Dijkmans et al.
4803731 February 7, 1989 Niiui et al.
5109419 April 28, 1992 Griesinger
5131051 July 14, 1992 Kishinaga et al.
5142586 August 25, 1992 Berkhout
5247474 September 21, 1993 Kowaki
5297210 March 22, 1994 Julstrom
5530762 June 25, 1996 Jones et al.
5555306 September 10, 1996 Gerzon
5621801 April 15, 1997 Kuwimuto et al.
Foreign Patent Documents
0335468 April 1989 EPX
0 480 561 April 1992 EPX
4022217 June 1991 DEX
4348399 December 1992 JPX
WO 93/23847 November 1993 WOX
Other references
  • Schroeder, M.R., "Improved Quasi-Stereophony and `Colorless` Artificial Reverberation, "J. Acous, Soc. Am., vol. 33, No. 8, Aug. 1961, pp. 1061-1064. Moorer, James A., "About This Reverberation Business, "Computer Music Journal, vol. 3, No. 2, pp. 13-28. Stautner, John; Puckette, Miller, "Designing Multi-Channel Reverberators, "Computer Music Journal vol. 6, No. 1, Spring 1982, pp. 52-65. Jot, Jean-Marc; Chaigne, Antoine, "Digital delay networks for designing artificial reverberators, "Presented at the 90th Convention Feb. 19-22, 1991, Audio Engineering Society. Parkin, P.H. & Morgan, K., "Assisted Resonance in the Royal Festival Hall, London: 1965-1969, "Journal of the Acoustical Society of America, Apr. 28, 1970, pp. 1025-1035. DeKoning, S.H., "The MCR System--Multiple-Channel Amplification of Reverberation, "Philips Tech, Rev. 41. No. 1, 1983/84, pp. 12-25. Kawakami, F. & Shimizu, Y., "Active Field Control in Auditoria, "Applied Accoustics 31 (1990) , pp. 47-75. Jones, M.H. & Fowweather, f., "Reverberation Reinforcement--an Electro-Acoustical System for Increasing the Reverberation Time of an Auditorium, "Acoustica, vol. 27 (1972) , pp. 357-363. Prinssen, Ir. W.C.J.M. & Holden, M., "System for Improved Acoustic Performance (SIAP) , "Proc, I.O.A. vol. 14, Part 2 (1992) pp. 93-101. Griesinger, David, "Improving Room Acoustics Through Time-Variant Synthetic Reverberation, "90th Convention Audio Engineering Society, Feb. 19-22, 1991. Berkhout, A.J., DeVries, D., & Vogel, P., "Acoustic Control by Wave Field Synthesis, "J. Acoust. Soc. Am. 93 (5), May 1993, pp. 2764-2778.
Patent History
Patent number: 5729613
Type: Grant
Filed: Apr 15, 1996
Date of Patent: Mar 17, 1998
Assignee: Industrial Research Limited
Inventor: Mark Poletti (Wellington)
Primary Examiner: Curtis Kuntz
Assistant Examiner: Xu Mei
Law Firm: Woodard, Emhardt, Naughton, Moriarty & McNett
Application Number: 8/624,547
Classifications
Current U.S. Class: Reverberators (381/63); Reverberation (84/630)
International Classification: H03G 300;